A variety of sensors can be attached on a human body or implanted into the human body to monitor or check the human body for various reasons. The sensors need power to operate, and they need to be frequently connected to a power source or have a battery replaced. These procedures are burdensome to the user of the sensors and require some time. Even though wireless power transfer (WPT) technology allows wireless power transfer to a receiver, such as one including a sensor, the current WPT technology requires the receiver to be positioned in a specific cite, thereby inhibiting the user of the sensor from moving.